jumpman2334

alright, tried searching. nothing came up. so here i go!

me and my dad tried to get my 280 that i bought 2 weeks ago running last night. and it wouldnt start. although it was turning and it sounded like it wanted to start. so after some trial and error stuff we figured out that the fuel lines were plugged, and no gas was getting to the motor. so aside from just needing to just blow out the fuel lines, is there anything else youd recommend that i do before i try and start it again?? just so nothing is over looked.

according from the lady that i bought it from, it hasnt ran for approx a year and a half.

heres everything that i did so far.
new oil
filter
mixed new gas with some of the old nasty gas already in it.
charged battery, still not sure if its good or not.

i also bought new spark plugs, spark plug wires, rotor cap, and a fuel filter. but i figured why not just run the old stuff for a few hundred miles and get as much crap out with the old stuff as i can, then put all the new stuff in. and i was going to change to a new oil and filter at about 1000 miles too. does that seem like a good idea to do? just to get all the old nasty crap out.

thanks!

NismoPick

So... is the fuel pump working? You also need a fully charged battery... let's not play the guessing game.

jumpman2334

so we think, but if we blow out the lines and we know there for sure unclogged, then itll be time for a new fuel pump. but there could be a chance that the pump isnt working. so thanks for that help.

and we did a slow trickle charge on the battery. i think itll work for now. but ill eventually be getting a new one.

hoov100

pull the drain plug on the tank and drain it all out, then peak in their and see how much varnish and rust is in their, if it checks out good, then your ok. also, you might as well toss the plugs, wires, cap and rotor on there to rule them out, next you can have someone stand next to the pump, while someone turns the key on, it should run until theirs pressure in the lines.

jumpman2334

awesome thanks for the help. ill get back to you on sunday, and let everyone know how everything goes!

BoulderZ

Given there was old and nasty gas in there, there's a good chacnce your fuel pump could be just stuck, along with the damper and check valve. While you're putting your new fuel filter in (because the old one is definitely gummed up by now), leave the line off of it and run it to a large (quart or so) container and have someone turn the key while you watch to see if clean new fuel is getting pumped up there. If not: one of the above is stuck, or perhaps the pump isn't getting power (simple test light). Hopefully the nasty gas hasn't clogged up your injectors. Don't try to burn up all the old gas. Drain it from the tank and dispose of it (lawn mower, household HazMat, whatever). It'll only cause problems in the car. Blowing out the lines, as you mentioned, will let you know that they're open. Just be sure not to blow air back through the fuel line to the pump from the engine without disconnecting it just ahead of the fuel pump/damper/checkvalve assembly. You can ruin the check valve (yes, I did that, and it's dumb).
cheers,
Dave

jumpman2334

well right now, we took off the fuel pump, cleaned it out, since it wouldnt even spin. and then hooked it up to a small ATV battery, (then mocked up a little fuel system on my work bench to see if it would work, and it did) and it was working great. then we put it on the car, but without any of the fuel lines hooked up, to see if fuel would come out, and we were turning the car, and the relays seemed to be working, they were ticking, and we still werent getting any power to the fuel pump. anyone know why?

BlueKitsune

Probably doing what my 280Z did, the second fuel pump relay (one with 4 prongs) would click, but power wasn't getting through it.

A way to test if the fuel pump is getting power though the relay without having to take stuff apart is connect your volt meter to the IAC Plug, its only gets power when the fuel pump does. (same relay)

theramz

You really need to download the FSM. The '78 fuel pump is wired through the oil pressure switch. If you lost the prime in the oil pump the fuel won't turn on. Cranking the engine with no oil or even sitting for a long time can cause this. I would remove the plugs and crank to check for oil pressure. Pump gas into a can like Dave said. A low battery will rob power from the ECU and coil during cranking too. You should always make sure everything is working before spark because in the confusion you might be puking oil or gas all over.
Be safe, Tom

BlueKitsune

You should read the FSM. The fuel pumps is ran through 2 relays, One of which has the input signal from the Alternator and oil pressure switch. if both are on or one is not hooked up, that relay triggers another relay, which then activates the fuel pump.

So basically, pull the connector off the Alternator or the Oil pressure switch and the fuel pump will run with the key on, but the engine not running or turning over

NismoPick

Did you just tell TheRamz to read the FSM? How does your explanation contradict his? You both mentioned the oil pressure switch... you elaborated.

I don't get it....

BlueKitsune

to me he made it sound like the fuel pump power is right though the pressure switch itself. So I was correcting it.

theramz

My bad, I ASSumed the alt and oil pressure was hooked up. The FSM doesn't mention gremlins disconnecting the wires. The FSM helps you check everything no matter if they were ripped out or simply failed from old age.
I had to look up your profile to find out what year you had., the '78 is different than the earlier 280s so make sure you download the right year!

jumpman2334

we have the FSM. like an actual copy. not the downloaded ones off the internet, we cant find anything in it thatll help us though.. were still trying to test out some other stuff. like make new fusable links? but other than that, we dont have many other options, since the relays seem to be working.

theramz

I don't have that year FSM but I know that the circuit is wired through the Alt and oil p switch. This is for safty and turns the pump off in the event of a stall. The fuel pump requires higher voltage draw so the relays turn on the power to it and check for all start conditions. I don't know if it is wired through the neutral switch but you will find out why the car was parked 1 1/2years ago. Some guys bypass the whole thing and just use a toggle switch from the battery to the pump.